In recent years, use of illumination devices such as LED lamps which use LED modules has become widespread. Preferably, a lamp for general illumination use should illuminate an object so that colors of the object can be viewed as desired. An established method for quantitatively rating quality of colors viewed when using various different illuminants is by using a color rendering index, which rates color rendering properties of an illuminant. The color rendering index is a quantitative measure of a how accurately the illuminant reproduces colors relative to a reference illuminant. Various arts have been proposed for improving color rendering properties as measured using the color rendering index described above. One example of such an art is increasing the number of different color phosphors combined with LEDs. For example, Patent Literature 1 discloses provision of a red phosphor in additional to conventional phosphors (refer to paragraph 0007).